Effect of barrier integrity on topical/transdermal delivery of diclofenac sodium via iontophoresis

Abstract

Introduction: Application of a drug product on compromised skin may result in altered drug delivery leading to potential systemic toxicity. In this study, we investigated the effect of barrier integrity on the topical and transdermal delivery of brand: generic pair of diclofenac sodium (model anti-inflammatory drug) via iontophoresis. Methods: In vitro drug permeation studies were performed on normal and compromised skin using vertical Franz diffusion cells. A compromised skin model was created using ten tape strips on dermatomed human skin. We compared marketed brand and generic formulations of diclofenac sodium (Voltaren� and 1% diclofenac sodium topical gel by Amneal) via cathodal iontophoresis (0.5 mA/cm2; 2h followed by passive delivery till 6h) using 700 �L of formulation. Results/Conclusion: No significant difference observed between brand and generic formulations for delivery of diclofenac sodium via normal (149.78�18.43�g/cm2(brand);145.53�12.61�g/cm2(generic)) and compromised skin (233.13�8.32 �g/cm2(brand); 242.07�11.17 �g/cm2(generic)). The total delivery of diclofenac was significantly higher for the brand-generic pair into and across compromised skin as compared to normal skin indicating the effect of barrier integrity on delivery of diclofenac sodium. However, there was no significant difference in skin delivery of diclofenac sodium for normal (94.18�15.08 �g/cm2 (brand); 76.97�14.15 �g/cm2 (generic)) and compromised skin (76.74�8.75 �g/cm2 (brand); 72.36�5.18 �g/cm2 (generic)).